Yes, you can remove the existing thermostats in the wall and install the Smart Thermostat X from tado°, but there are a few steps and considerations you should bear in mind:

- Compatibility: Make sure that the Smart Thermostat X is compatible with your underfloor heating system. tado° offers a compatibility checker that you can use to verify that the device works with your heating system.

- Preparation: Switch off the circuit for your heating system at the fuse box before you start. This is important for safety during installation.

- Removal and installation: Remove the existing thermostat and follow the instructions in the tado° app to install the new Smart Thermostat X. You may need a screwdriver to make the connections.

- Instructions: Scan the QR code on the device with the tado° app for step-by-step installation instructions. The app provides specific instructions based on your heating system.

- Connection: Make sure the device is correctly wired and connected. The Smart Thermostat X usually only requires two cable connections if it is battery powered.

By following these steps, you can successfully install the Smart Thermostat X and make your underfloor heating smart.